I have a small fan motor that I need to replace, the fan is mounted on
an aluminium (I think) collar which is siezed on the shaft.

So, what's a good approach to getting it unstuck? I've drilled out
most of the grub screw that should be holding it, I doubt that's the
issue now. It's just that the collar is very firmly stuck on the
shaft.

There's lots of "how to get steel studs out of aluminium cylinder
blocks" advice I can find on the web but my problem is the other way
around. Is there anything in particular that might help apart from
all the usual things like soaking in penetrating oil, bashing it,
etc.?

It's quite small, the shaft is about 7mm (possibly 1/4") diameter. The
end protrudes only 1cm or so beyond the fan, I can hold it in a vice
quite firmly but the fan is quite flimsy so brute force rotation of
that is rather difficult.

--
Chris Green
·

On 29/11/2019 13:07, Chris Green wrote:
I have a small fan motor that I need to replace, the fan is mounted on
an aluminium (I think) collar which is siezed on the shaft.

So, what's a good approach to getting it unstuck? I've drilled out
most of the grub screw that should be holding it, I doubt that's the
issue now. It's just that the collar is very firmly stuck on the
shaft.

There's lots of "how to get steel studs out of aluminium cylinder
blocks" advice I can find on the web but my problem is the other way
around. Is there anything in particular that might help apart from
all the usual things like soaking in penetrating oil, bashing it,
etc.?
Heat will do it. Also, try knocking the collar down the shaft a short
way (perhaps with a suitable "socket" or box spanner)

It's quite small, the shaft is about 7mm (possibly 1/4") diameter. The
end protrudes only 1cm or so beyond the fan, I can hold it in a vice
quite firmly but the fan is quite flimsy so brute force rotation of
that is rather difficult.

On 29/11/2019 13:07, Chris Green wrote:
I have a small fan motor that I need to replace, the fan is mounted on
an aluminium (I think) collar which is siezed on the shaft.

So, what's a good approach to getting it unstuck? I've drilled out
most of the grub screw that should be holding it, I doubt that's the
issue now. It's just that the collar is very firmly stuck on the
shaft.

snip

The coefficient of thermal expansion of Aluminium is about twice that of
steel, so I'd try heating it. Aluminium conducts much better too.

Hot oil might do it.

Cheers
--
Clive

On 29/11/2019 13:27, Clive Arthur wrote:
On 29/11/2019 13:07, Chris Green wrote:
I have a small fan motor that I need to replace, the fan is mounted on
an aluminium (I think) collar which is siezed on the shaft.

So, what's a good approach to getting it unstuck?Â* I've drilled out
most of the grub screw that should be holding it, I doubt that's the
issue now.Â* It's just that the collar is very firmly stuck on the
shaft.

snip

The coefficient of thermal expansion of Aluminium is about twice that of
steel, so I'd try heating it.Â* Aluminium conducts much better too.

Hot oil might do it.

Cheers
+1 and a puller is handy.


--
€œProgress is precisely that which rules and regulations did not foresee,€�

€“ Ludwig von Mises

Clive Arthur wrote:
On 29/11/2019 13:07, Chris Green wrote:
I have a small fan motor that I need to replace, the fan is mounted on
an aluminium (I think) collar which is siezed on the shaft.

So, what's a good approach to getting it unstuck? I've drilled out
most of the grub screw that should be holding it, I doubt that's the
issue now. It's just that the collar is very firmly stuck on the
shaft.

snip

The coefficient of thermal expansion of Aluminium is about twice that of
steel, so I'd try heating it. Aluminium conducts much better too.

Hot oil might do it.

Sounds a good approach, I'll get my (relatively) new gas blow torch
onto the job.

--
Chris Green
·

The Natural Philosopher wrote:
On 29/11/2019 13:27, Clive Arthur wrote:
On 29/11/2019 13:07, Chris Green wrote:
I have a small fan motor that I need to replace, the fan is mounted on
an aluminium (I think) collar which is siezed on the shaft.

So, what's a good approach to getting it unstuck?Â* I've drilled out
most of the grub screw that should be holding it, I doubt that's the
issue now.Â* It's just that the collar is very firmly stuck on the
shaft.

snip

The coefficient of thermal expansion of Aluminium is about twice that of
steel, so I'd try heating it.Â* Aluminium conducts much better too.

Hot oil might do it.

Cheers
+1 and a puller is handy.

There's really nothing to get hold of with a puller, the fan is in the
way.

--
Chris Green
·

Unless the fan itself is plastic, in which case it will be a mess.

A bit of oil down the grub hole and either end, then gentle tapping of the
spindle to see if it moves after a few hours. However if you have drilled
the grub screw hole, how are you going to re attach the fan to a new motor?
Brian

--
----- --
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please
Note this Signature is meaningless.!
"Clive Arthur" wrote in message
...
On 29/11/2019 13:07, Chris Green wrote:
I have a small fan motor that I need to replace, the fan is mounted on
an aluminium (I think) collar which is siezed on the shaft.

So, what's a good approach to getting it unstuck? I've drilled out
most of the grub screw that should be holding it, I doubt that's the
issue now. It's just that the collar is very firmly stuck on the
shaft.

snip

The coefficient of thermal expansion of Aluminium is about twice that of
steel, so I'd try heating it. Aluminium conducts much better too.

Hot oil might do it.

Cheers
--
Clive

"Brian Gaff \(Sofa 2\)" wrote:
Unless the fan itself is plastic, in which case it will be a mess.

A bit of oil down the grub hole and either end, then gentle tapping of the
spindle to see if it moves after a few hours. However if you have drilled
the grub screw hole, how are you going to re attach the fan to a new motor?

By drilling and tapping a new grub screw hole. :-)

Or by cleaning out the existing one, I haven't drilled it out so far
that the thread has gone, however I'm not sure I'll be able to clean
out the remains of old grub screw.

--
Chris Green
·

On 29/11/19 13:07, Chris Green wrote:
I have a small fan motor that I need to replace, the fan is mounted on
an aluminium (I think) collar which is siezed on the shaft.

So, what's a good approach to getting it unstuck? I've drilled out
most of the grub screw that should be holding it, I doubt that's the
issue now. It's just that the collar is very firmly stuck on the
shaft.

There's lots of "how to get steel studs out of aluminium cylinder
blocks" advice I can find on the web but my problem is the other way
around. Is there anything in particular that might help apart from
all the usual things like soaking in penetrating oil, bashing it,
etc.?

It's quite small, the shaft is about 7mm (possibly 1/4") diameter. The
end protrudes only 1cm or so beyond the fan, I can hold it in a vice
quite firmly but the fan is quite flimsy so brute force rotation of
that is rather difficult.

If the other methods don't work, and the collar really is aluminium and
the shaft steel, then immersing it in concentrated caustic soda will
dissolve the aluminium and leave the steel untouched. It is unlikely
that the plastic will be affected (unless it's polycarbonate or PETE,
although these would be unlikely to be used as fan blades), but it might
melt if the reaction gets too hot.

A note of caution, however; it isn't called "caustic soda" for nothing.
Eye protection is essential, and so are decent length gloves.

--

Jeff

On Fri, 29 Nov 2019 14:00:38 +0000, Chris Green wrote:

Sounds a good approach, I'll get my (relatively) new gas blow torch
onto the job.

Alternatively, use cold.

There's a variety of "rust shock" sprays that combine oil and some gas that
cools on contact. Even if the ally gets tighter on steel with cold, it may help
as it may stretch, and then be looser as it warms up again, IYSWIM.

And less chance of melting the nearby plastic...

Thomas Prufer

In article ,
Chris Green wrote:
The coefficient of thermal expansion of Aluminium is about twice that
of steel, so I'd try heating it. Aluminium conducts much better too.

Hot oil might do it.

Sounds a good approach, I'll get my (relatively) new gas blow torch
onto the job.

You could try putting the whole thing in boiling water first. That won't
melt anything. ;-)

--
*I used up all my sick days so I called in dead

Dave Plowman London SW
To e-mail, change noise into sound.

On 29/11/2019 13:07, Chris Green wrote:
I have a small fan motor that I need to replace, the fan is mounted on
an aluminium (I think) collar which is siezed on the shaft.

So, what's a good approach to getting it unstuck? I've drilled out
most of the grub screw that should be holding it, I doubt that's the
issue now. It's just that the collar is very firmly stuck on the
shaft.

There's lots of "how to get steel studs out of aluminium cylinder
blocks" advice I can find on the web but my problem is the other way
around. Is there anything in particular that might help apart from
all the usual things like soaking in penetrating oil, bashing it,
etc.?

It's quite small, the shaft is about 7mm (possibly 1/4") diameter. The
end protrudes only 1cm or so beyond the fan, I can hold it in a vice
quite firmly but the fan is quite flimsy so brute force rotation of
that is rather difficult.

Steel on aluminium can be a bugger. If the motor is dead, I'd be
inclined to destroy the motor in an attempt to save the fan. Angle
grinder, dremel, etc. depending on the size. Once you have the fan with
just an inch of motor spindle it becomes comparatively easy, I'd start
by removing the grub screw, soaking the lot in penetrating fluid of your
preference, and then finding suitable spacers to let you push the
spindle out in a press, or a pillar drill, or a vice. Once it has moved
a bit it should be easier to remove e.g. with a mole wrench.

In article ,
says...

I have a small fan motor that I need to replace, the fan is mounted on
an aluminium (I think) collar which is siezed on the shaft.

So, what's a good approach to getting it unstuck? I've drilled out
most of the grub screw that should be holding it, I doubt that's the
issue now. It's just that the collar is very firmly stuck on the
shaft.

There's lots of "how to get steel studs out of aluminium cylinder
blocks" advice I can find on the web but my problem is the other way
around. Is there anything in particular that might help apart from
all the usual things like soaking in penetrating oil, bashing it,
etc.?

It's quite small, the shaft is about 7mm (possibly 1/4") diameter. The
end protrudes only 1cm or so beyond the fan, I can hold it in a vice
quite firmly but the fan is quite flimsy so brute force rotation of
that is rather difficult.

You obviously never learned how they fit the (steel) tyres on
the wheels of railway vehicles!

(I must have been about 10 when I came across it in Arthur
Mee's Childrens' Encyclopedia!)

--

Terry